The device relates to an oil cooler formed by stacking a plurality of plates.
As a conventional oil cooler formed by stacking a plurality of plates, one that is disclosed, e.g., in Japanese Utility Model Unexamined Publication No. 121270/1988 is known. FIGS. 8 to 10 show the oil collar disclosed in the above-mentioned publication. In FIGS. 8 to 10, reference numeral 1 designates a core portion having cooling water passages 7 and oil passages 9 between plates 3, 5 that are formed by alternately stacking the plurality of plates 3, 5. An upper plate 19 is firmly fixed on the upper end surface of the core portion 1. The upper plate 19 has an opening 11 in the middle and three openings 13, 15, 17 around the opening 11.
The two diametrically opposed openings 13, 15 communicate with the cooling water passages 7, and the opening 17 communicates with the oil passages 9. Water pipes 21, 23 are coupled to both openings 13, 15. A reinforcing partition plate 27 formed of an expanding portion 25 that covers both the opening 17 communicating with the oil passages 9 and the opening 11 arranged in the middle of the upper plate 19 is mounted on the upper plate 19.
In FIG. 9, reference numeral 29 designates a lower plate secured to the lower end surface of the core portion 1. In the middle of the lower plate 29 is an opening 31 formed so as to correspond to the opening 11. Further, an opening (not shown) communicating with the oil passages 9 is arranged so as to correspond to the opening 17.
According to the thus constructed oil cooler, cooling water introduced from a hose (not shown) connected to one 21 of the water pipes is discharged to a hose (not shown) connected to the other water pipe 23 via the cooling water passages 7 of the core portion 1. Oil introduced into the core portion 1 from the opening of the lower plate 29 is heat-exchanged with the cooling water while flowing through the oil passages 9 and reaches the expanding portion 25 from the opening 17.
However, as shown in FIG. 10, the water pipes 21, 23 of the oil cooler 1 are of a so-called cantilever-type support structure with insertion-side ends 21a, 23a thereof being simply inserted into the openings 13, 15 of the upper plate 19, respectively. Therefore, a shortcoming that the mounting strength of the water pipes 21, 23 is not sufficient against external stresses (e.g., a force applied when the water pipes are being inserted into the hoses, vibrations of the hoses, etc.).